The invention relates to a photodetector which can be operated n at least two wavelength ranges and a method of making the same. The invention is used for photovoltaic detectors and solar cells.
Photodetectors operating in the two-wavelength mode have been disclosed for III/V compound semiconductor materials (Friedmann et al. in Compound Semiconductor, page 27, November/December 1996). Photodetectors of this type have a relatively low efficiency. Moreover, the spectral sensitivity is merely determined by a single semiconductor material.
Therefore, it is the object of the present invention to provide a photodetector with high efficiency which can be operated at least in two wavelength ranges.